function createXMLHttpRequest()
{
   var result;
   if (window.XMLHttpRequest) {
      // code for IE7+, Firefox, Chrome, Opera, Safari
      result=new XMLHttpRequest();
   }
   else if (window.ActiveXObject) {
      // code for IE6, IE5
      result=new ActiveXObject("Microsoft.XMLHTTP");
   }
   else {
      result = null;
   }

   return result;
}